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Diatoms of North America provides analysts, academics and managers with tools for diatom taxonomy, nomenclature and ecology

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Federal, tribal, state and local agencies use Diatoms of North America to monitor water quality and comply with the Clean Water Act

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We aim to create a comprehensive diatom flora, accessible to everyone

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Over 100 contributing taxonomists, from students-in-training to seasoned professionals, collaborate in producing an ambitious flora

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Diatoms of North America is a collaborative work in progress, growing and changing as science advances.

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Taxon Contributors

Contributors produce comprehensive documentation on diatoms, leading to consistent and correct taxonomy.

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Taxa by Morphology

New to diatoms? Jump into diatom identification using the visual key.

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Editorial Review Board

Using diatoms in assessment? Specify the use of Diatoms of North America in contracts and task agreements.

What are Diatoms?


Diatoms are single-celled algae that live nearly everywhere there is water - streams, ponds, lakes, oceans, and even soils.

For practitioners

Identification Guide



Classification information, citations, links and species listings for 182 genera completed to date.



Identification guides, original descriptions, citations, autecological information and more for 1058 species and growing.


We encourage new contributors to submit taxon pages.

This project depends on many people to document the diverse diatom flora of streams, rivers, wetlands, lakes, springs, soils, estuaries and coastal zones.

Recent News & Projects

Sarah Crump Graduate Fellowship

Unfortunately, Sarah was diagnosed with a rare and aggressive form of cancer in April 2022. After a hard-fought battle, the cancer spread, and she...


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Winter Solstice Party

The International Society for Diatom Research (ISDR) is sponsoring an online Winter Solstice Party on December 21, 6:00 PM eastern (US and Canada)....

Happy Holidaze

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Diatom Web Academy 2023

We are back and looking ahead to spring 2023! Would you like to be part of Diatom Web Academy? We welcome participation by diatomists at every...

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Diatoms of North America has been developed in part with the generous funding and support of US EPA, USGS, the Institute of Arctic and Alpine Research at University of Colorado Boulder and other organizations.

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